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| United States Patent |
6,170,986
|
|
Hsu
, et al.
|
January 9, 2001
|
Linear motion rolling guide device
Abstract
A linear motion guide device includes a rail, a slider and a plurality of
rolling elements. Two identical injection molded side frames having two
end-plates with convex half-roundness on both ends of a longitudinal
arranged profiled member with the same length as steel body, are
bilaterally attached to the outside of the elongation of the steel body
and the steel body is longitudinally situates inside and attached to the
endplate. At least one return passage of the rolling elements is provided
outside of the elongation of the steel body. A pair of end caps with
concave half-roundness and end seals is externally attached to the
endplates. The steel body, the side frames, and the end caps having means
for attachment are therefore properly positioned to each other. A compact
sealing design is also provided.
| Inventors:
|
Hsu; Ming-Che (Taipei, TW);
Chen; Shyuan-Jye (Taichung, TW);
Hong; Chih-Chieh (Yuan-Ho Taipei Hsien, TW);
Chang; Kuei-Hsin (Chu Tung Hsinchu Shien, TW)
|
| Assignee:
|
Chieftech Precision Co., Ltd. (Chung-Li City, TW)
|
| Appl. No.:
|
287967 |
| Filed:
|
April 7, 1999 |
| Current U.S. Class: |
384/15; 384/13; 384/45 |
| Intern'l Class: |
F16C 031/06 |
| Field of Search: |
384/13,15,43,44,45
|
References Cited
U.S. Patent Documents
| Re35323 | Sep., 1996 | Ohtake | 384/15.
|
| 4637739 | Jan., 1987 | Hattori | 384/45.
|
| 5080498 | Jan., 1992 | Tsukada | 384/15.
|
| 5102235 | Apr., 1992 | Mugglestone | 384/45.
|
| 5340219 | Aug., 1994 | Agari | 384/15.
|
| 5435649 | Jul., 1995 | Kuwahara | 384/13.
|
| 5451109 | Sep., 1995 | Ichida | 384/15.
|
| 5951168 | Sep., 1999 | Teramachi et al. | 384/45.
|
| Foreign Patent Documents |
| 19538665 | Apr., 1997 | DE.
| |
| 474948 | Mar., 1992 | EP.
| |
Primary Examiner: Hannon; Thomas R.
Attorney, Agent or Firm: Liauh; W. Wayne
Claims
What is claimed is:
1. A linear motion rolling guide device comprising:
a longitudinally extended rail including at least one raceway on both right
and left sides, a plurality of rows of rolling elements and a slider, by
means of the rolling of said rolling elements between the raceway of the
rail and its opposite facing race way on the slider respectively, sliding
relative to the rail;
the slider further comprising:
a steel body with two downward elongations on both sides, whose opposite
inside surfaces having longitudinally extended race way grooves formed;
a pair of identical injection molded side frames, including a
longitudinally arranged profiled member having the same length as the
steel body, two transversely arranged endplates, perforated by the return
passage and wherefrom having a convex half-roundness stretched, on both
end of the profiled member, wherein a return passage of the said rolling
elements is formed and defined when the side frames are bilaterally
mounted to the outer surface of the said elongation and the steel body
longitudinally situated inside and attached to the endplates; and
a pair of end caps externally attached to the said endplates, including at
least a pair of concave half-roundness;
whereby the steel body, the side frames and the end caps have means for
attachment and are thereof positioned to each other and the turnaround
channel, which is formed by the concave half-roundness on the end caps and
the convex half-roundness on the endplates, connects thereof endwise with
the said race way grooves and the said return passage to form a
circulation passage way for the rolling elements re-circulation.
2. A linear motion rolling guide device according to the claim 1, wherein
the means for attachment of the steel body, the side frames and the end
caps include an interlocking means on the endplates and a pair of slots on
the end caps;
whereby by fitting the dimension of the width between the outside surface
of the elongation to the dimension of the width between the two slots, the
steel body, the side frames and the end caps are fixedly attached to each
other bilaterally when the interlocking means are firmly connected with
said two slots.
3. A linear motion rolling guide device according to the claim 2, wherein
the outer surface of the said elongation has a forcipiform with an opening
laterally toward outsides and the profiled member has a mating form to
said forcipiform so that the side frames are vertically and laterally
complete positioned to the steel body when the side frames are laterally
fixedly attached to the steel body.
4. A linear motion rolling guide device according to the claim 2, wherein
said interlocking means and said counterparts provide the positioning
duty; through their engagement the end caps and the side frames are
thereof direct positioned to each other.
5. A linear motion rolling guide device according to the claim 2, wherein
at least one longitudinal extended snap means is integrated on the
endplate of the side frame by the interlocking means.
6. A linear motion rolling guide device according to the claim 5, wherein
the said snap means also fix the end seals longitudinally on the outside
of the end caps by snapping the counterparts on the end seals; the end
seals are transversely positioned and fixed by inserting the
longitudinally arranged positioning pin on the outside surface of the end
caps into the positioning holes on the end seals.
7. A linear motion rolling guide device according to the claim 6, wherein
said end seals have a rigid back and an elastic layer which close the
slots on the steel back to a smaller window so that an unexpected
disengagement of the snap means from the interlocking position is
prevented.
8. A linear motion rolling guide device according to the claim 1, wherein
the longitudinally arranged closed through hole as the return passage of
the rolling elements is molded inside the profiled member.
9. A linear motion rolling guide device according to the claim 8, wherein
the said return passage of the rolling elements is integrated with at
least one longitudinally arranged groove molded inside the profiled member
for lubrication deposit.
10. A linear motion rolling guide device according to the claim 8, which
further comprises a pair of under seals with a laminated structure having
a thin rigid back;
a longitudinal rib is bent upwards on an outer edge of the rigid back and
fit into a longitudinally arranged gap between the profiled member and the
elongation.
11. A linear motion rolling guide device according to the claim 1, wherein
the cross section shape of the outer surface of the elongation of the
steel body and the opposed facing surface on the profiled member comprise
each at least one convex groove which fit together to form at least one
longitudinal arranged closed through hole as the return passage of the
rolling elements.
12. A linear motion rolling guide device according to the claim 11, wherein
a projection overhead on the end plate of the side frame, is engaged in
the recess on both ends of the top face of the steel body and press the
steel body from the top vertically downward to have a firm contact and
exact positioning on the profiled member.
13. A linear motion rolling guide device according to the claim 1, wherein
a longitudinal extended side wall is integrated on the endplate of the
side frame; said side wall extends the lateral side of profiled member
longitudinally to secure the joint of the turnaround channel and the
return passage being covered by the side wall and avoid a direct invasion
of the dusts.
14. A linear motion rolling guide device according to the claim 1, wherein
a pair of retainers made from steel wire or string are provided against
the drop out of the rolling elements from the slider when it is separated
from the rail; its both ends are held and positioned by the recess on the
end caps; on each rows of the rolling elements on the said rail a relief
groove is provided against the contact with the retainer.
15. A linear motion rolling guide device according to the claim 1, wherein
a lubrication hole is in the middle of the end cap and a laterally
symmetric arranged lubrication channel connects the lubrication hole and
the turnaround channel on bilateral side so that the lubricant can be
filled from the lubrication hole into the re-circulation passage ways of
the rolling elements; the lubrication channel is formed and closed when
the end cap is fixed attached to the endplate of the side frames; to avoid
the leakage of lubricant from the joint gap of the endplates, a design
with longitudinally overlapped projection extended laterally from the
joint of the two side frames and a design with overhangs extended from the
end cap to close the joint gap from top and bottom are provided.
16. A linear motion rolling guide device comprising:
a longitudinal extended rail including a raceway on the right-and-left
side; and
a slider, by means of the rolling of a plurality of rows of rolling
elements between the raceway on the right-and-left side of the rail and an
opposite facing race way on the slider respectively, sliding relative to
the rail; and
a pair of end seals on both ends of the slider each having a elastic layer;
the elastic layer is molded with a plug, having the same form as and formed
aligned to a lubrication hole on the slider for the lubrication injection
from outward; the plug is partially connected with said layer and thereof
can be unfolded while lubrication injection and plugged into said
lubrication hole when the lubrication injection is fulfilled, so that the
leakage of the lubricant from said lubrication hole is prevented.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a linear rolling guide device suitable for
relatively small equipment including office automation and measuring
equipment.
In the conventional design a linear motion rolling guide assembly has a
rail and a slider, through the rolling of a plurality of rows of rolling
elements, riding and sliding on the rail.
The slider includes a steel body with an elongation extending downwards on
both sides of a steel plate. A plurality of pairs of longitudinally
arranged grooves, provided as tracks of the rolling elements, are formed
on inside faces of the elongation. A plurality of pairs of holes as return
passages of the rolling elements is drilled through the elongation. Two
end caps, including the turnaround channel, which connects the track of
rolling elements and the return holes, are mounted on both end faces of
the steel body by fixing screws.
The smaller the hole is, the more difficult it is to drill. To overcome the
manufacturing difficulty designs of return hole, formed by an open groove
and a closure, member are provided, see the U.S. Pat. No. 4,637,739, and
European patents EP 0 494 682 A2 and EP 0 474 948 A1.
EP 0 494 682 A2 and EP 0 474 948 A1, taught an alternative design which
simplifies the manufacture and mounting complexity.
In the EP 0 494 682 A2 the disclosed interlocking design by using a
snapping means, which is integrally formed on the longitudinal end of the
closure member of the return track, to fix two monolithically end caps
with a return track. The space of the snap means is limited by the shape
of the closure member, which is also constrained laterally by the mounting
holes for the connection of the surrounding part designed to slide
relative to the rail, and vertically by the fitting edge for the
surrounding part. A firm interlocking of the snap means, especially for
the small size linear rolling guide device, is difficult to achieve.
In DE 195 38 665 A1 another snapping design is disclosed. A casement enfold
the bottom of the steel body and form the ball return tracks space in
between, two end caps are inserted vertically from top into the axial
space between the endplate of the casement and the end face of the steel
body. These two end caps press the steel body down to the casement by the
projection overhead and are fastened vertically on the casement by using a
snapping mean on the endplate of the casement and the outside face of the
end cap. The casement provides positioning surfaces for the steel body and
the end caps, respectively. A disadvantage of this is the indirect
positioning between the end caps and the steel body. This elnarges the
misalignment between the return channel and the turn-around channels of
the rolling elements and causes an unsatisfactory rolling element
re-circulation.
The conventional and economical fabrication of the precision plastic
injection molding can achieve an positioning and form accuracy of ca.
.+-.0.02 mm relative to a length 0.5.about.1.5 mm; and the minimal fillet
radius/chamfer can achieve an accuracy of 0.1 mm. Any higher accuracy
requirement will substantially increase the manufacturing cost. Such
inaccuracy and the minimum fillet limit the minimization of the linear
motion rolling guide device. A firm and accurate interlocking is secured
only if the fitting surfaces of the parts to be attached together are
large enough and are precisely conformed to each other. The smaller the
linear motion rolling guide device is, the smaller is the fitting surface.
This also limits the maximum extent of minimization of the dimensions.
SUMMARY OF THE INVENTION
Therefore, the object of this invention is to provide a linear guide device
to solve the above mentioned problems and to furthermore minimize the
dimensions thereof without increasing the manufacturing cost.
According to the above-mentioned object there is provided a linear motion
rolling guide device including a longitudinal extended rail, a plurality
of rows of rolling elements, a slider. By means of the rolling of the
rolling elements between the raceway on the right-and-left side of the
rail and the opposite facing race way on the slider, the linear motion
rolling guide device slides relative to the rail. The slider further
includes a steel body with an elongation extending downward on both sides
of a base plate. The outside surface of the elongation, provided as the
fitting and positioning surface for the attachment of the side frames, has
a forcipiform with an opening laterally towards outside.
A pair of injection molded side frames are provided each has a
longitudinally arranged profiled member having the same length as the
steel body and two transversely arranged end plates on both end of the
profiled member in one single mold. The profiled member, bilaterally
engaged into the forcipiform of the elongation, are vertically fixed to
the steel body when the fitting profile are laterally and fixedly attached
to the outside surface of the elongation. The full use of the outside
surface of the elongation as fitting surface provides a firmer attachment
between the side frames and the steel body. This design can further
minimize the dimensions of the linear rolling guide device, compared to
those without full use of the outside surface as fitting surface. At least
one longitudinally arranged all-round closed hole is formed inside the
profiled member as the return passage of the rolling elements.
The endplates longitudinally constraining the steel body in between are
formed by a transversely arranged base plate, perforated by the return
passage and has at least one convex half-roundness on the base plate,
stretching from the inside surface of the return passage without any
misalignment in between and provided as the internal guiding surface of
the turnaround channel.
Two end caps are externally attached to the endplates, each has at least
one pair of concave half-roundness. The two end caps, together with the
convex half-roundness, form a closed turnaround channel. The end of the
concave half-roundness aligns to the end of the return passage more
precisely by direct positioning between the end caps and the side frames.
This brings a smoother running of the rolling element re-circulation.
The steel body, the side frames, and the end caps have means for attachment
and positioned to each other.
Such means of attachment is preferably formed by an interlocking means on
the endplates, such as tenon, and a pair of its counterparts on the end
caps, such as slots. The end caps interlock the two side frames crossly
together by engaging the interlocking means on the endplates with their
counterparts on the end caps. As a result the two opposed side frames are
forced to approach each other to within a certain distance defined by the
distance between the two counterparts. The width of the two opposed
outside surface of the elongation of the steel body is designed to meet
the distance between the two opposing side frames so that the side frames
are firmly attached to and clamp the steel body bilaterally tightly with a
certain pressure. The end caps are also transversely and fixedly fixed and
positioned to the side frames through the engagement of the interlocking
means and their counterparts. The engagement between the positioning
means, preferably the same as the interlocking means, on the endplates and
their inter-fitting means, preferably the same as the counter parts, on
the end caps, brings a direct positioning between the end caps and the
side frames. A pair of snap means is longitudinally integrated on the
endplates, preferably direct on the counterparts, such as tenon, for
saving space, to interlock the end caps on the front and rear end of the
slider longitudinally without using screws.
The side frames are fabricated by an injection molding process from
engineering plastic or with metallic powder having a molding die with
additional bilaterally sliding dies. The through holes as return passage
of the rolling elements are injection molded by a through pin having the
same form as and a length slightly longer than the through hole. The
through pin is integrated on a molding die of the endplate. On the other
molding die of the endplate a guiding hole is provided. The end of the
through pin is precisely engaged and supported by the guiding hole when
the molding dies are closed. The outside form of the profiled member is
injection-molded from another different molding dies.
In an alternative embodiment the longitudinally arranged return passage is
near half closed by the profiled member. The rest near half surface of the
through holes are form by a portion of the outside surface of the
elongation of the steel body. Such design simplifies the molding dies
without the need of the through pin on one side, but on the other side the
outside surface of the elongation is only partially used as fitting
surface. The near half surface of the return passage provided by the
profiled member becomes part of and is thereof injection-molded together
with the outside form of the profile member. The rest portion profile of
the profiled member is still provided as fitting surface for the
attachment to the elongation of the steel body. The necessary accurate
alignment of the perforated hole on the endplates to the concave
half-roundness of the end caps and the through hole respectively for the
smooth running of the rolling elements is achieved by the direct
positioning of the side frames and the end caps and steel body.
Two end seals are formed by a rigid layer such as steel sheet, having a
pair of slots, and an elastic layer such as molded by rubber. The end
seals will be longitudinally fixed attached to the outer end of the end
caps through the engagement of the slots with the same snap means on the
endplate of the side frames on the slider. Because of the dimension of the
small sized linear rolling guide device the lubrication hole can not be
attached with a grease nipple any more. The elastic layer is molded with a
plug, having the same form as and aligning to the lubrication hole on the
end caps of the slider and partially connected with the elastic layer and
thereof can be unfolded for lubrication injection and plugged into the
lubrication hole after the lubrication injection is fulfilled, so that the
leakage of the lubricant from the lubrication hole is prevented. The
elastic layer comprises a sealing lip, having the same shape as the
profile of the rail, which provides a contact sealing effect.
A pair of under seals are provided each has a thin rigid back, such as
steel sheet, and an elastic layer, such as molded from rubber. To achieve
the same rigidity as the thick rigid back, a rib is bent along on the
longitudinally outer edge of the thin rigid back. On the both ends of the
rigid back, a projection is bent vertically upwards and then
longitudinally outwards. The under seals are fastened and positioned to
the slider by inserting the projections into the recess on the bottom of
the end caps. As an alternative embodiment, the projections are inserted
into the recesses formed on the end seals. Such an interlocking design
allows the bottom of the end caps and the end seals to have the same
height as the bottom of the steel body and does not reduce any space of
the clearance from the bottom of the rail to the bottom of the slider. Any
clearance will only reduce the thickness of the under seals when the under
seals are mounted. A compact design is thereof achieved. The elastic layer
provides a longitudinally extended sealing lip to prevent the dusts or
particles entering into the raceway of the rolling elements from bottom.
To prevent the dropout of the rolling elements when separating the slider
from the rail, a retainer, having a straight portion and two holding
portions on both ends, respectively, made from a steel string or wire is
provided. Through the accurate positioning of the holding porting to the
end caps the longitudinally arranged straight portion is situated in the
same height as the rolling elements vertically and in the adjacent outside
of the rolling elements laterally. Whereas the width between the retainer
and the edge of the raceway of the steel body is smaller than the diameter
of the rolling elements and rolling elements are thereof hold in between.
An escaping recess on the raceway of the rail is provided, so that there
is no contact between the rail and the retainer happened when the slider
slides on the rail. The holding portion has a first portion transversely
and laterally bent outward and a second portion transversely and
vertically bent upward. The vertical and the lateral positionings of the
retainer are defined by the engagement of the recesses on the outer end of
the end caps with the first and the second portion respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features, and advantages of the invention will become
apparent from the following detailed description of the preferred but
non-limiting embodiments. The description is made with reference to the
accompanying drawings in which:
FIG. 1 is a perspective view of the explosive linear motion rolling guide
device of the present invention.
FIG. 2 is a cross-section view taking along the middle of the slider
FIG. 3 is a sectional view taking along II--II in FIG. 2 for description of
the ball re-circulation.
FIGS. 4A and 4B is a perspective view of the side frame.
FIG. 5 is a cross-sectional view taking along the middle of the slider
showing another example with near half-enclosed through hole.
FIG. 6 is a perspective view from front end of the end cap.
FIG. 7 is a perspective view from rear end of the end cap.
FIG. 8 is a perspective view from front end of the end seals.
FIG. 9 is a perspective view from rear end of the end seals.
FIG. 10 is a partial transverse-sectional view of the portion of the snap
interlocking between the side frame, the end cap and the end seal.
FIG. 11 is a longitudinal cross-sectional view of the portion of the plug
design of the end seal mounted to the end cap.
FIG. 12 is a perspective view of the under seals.
FIGS. 13A and 13B is a longitudinal cross-sectional view of the potion of
the interlocking between the under seal, the end cap, the side frame and
the end seal in assembly.
FIG. 14 is a perspective view of the retainer.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings FIG. 1 shows a linear motion rolling guide device
which includes a longitudinally extended rail 1, a plurality of rows of
rolling elements 3, a slider 2, and, by means of the rolling of the
rolling elements between the raceway 11 on the right-and-left side of the
rail and the opposite facing race way 21 on the slider 2, slides relative
to the rail. The slider 2 further includes a steel body 20, a pair of side
frames 30 having a profiled member 31 and two transversely arranged
endplates 32 on both ends bilaterally mounted to the steel body 20. The
steel body 20 is situated between the two endplates 32. A pair of end caps
50 are longitudinally attached to the slider 2 from fore-and-rear end, and
the steel body, the pair of side frames and the pair end caps 50 have
means for attachment and positioning to each other; a pair of end seals 70
attached to the outer end of the end caps 50 and a pair of the under seals
80 having a contact sealing lip 85 (shown in FIG. 8) to the right-and-left
side surface of the rail 1 attached to the bottom of the slider 2.
Referring to FIG. 2, the steel body 20 has two elongations 22 extending
downwardly on both sides of a base plate 23. The mounting face on the top
24 and side 25 for the connection to the surrounding parts are designed to
slide relative to the rail 1 and the longitudinally arranged grooves 21 as
raceway of the rolling elements 3 on the inside surface of the elongation
22 of the steel body 20. The outside surface 26 of the elongation 22,
provided as the fitting and positioning surface for the attachment of the
side frames 30, has a forcipiform with an opening laterally disposed
towards the outside.
A pair of side frames 30, having the fitting profile 42 on the outside
surface of the profiled member 31, are firmly engaged into the forcipiform
of the elongation 22 bilaterally and are vertically fixed and positioned
to the steel body 20, when the fitting profile 42 are laterally fixed
attached to the outside surface 26 of the elongation 22. The full use of
the outside surface 26 of the elongation as fitting surface provides a
firmer attachment between the side frames 30 and the steel body 20. The
dimensions of the linear rolling guide device can therefore be further
minimized as compared to those without full use of the outside surface 26
as fitting surface. At least one longitudinally arranged all-round closed
hole 33 is formed inside the profiled member 31 as the return passage of
the rolling elements 3.
Referring to FIG. 3, at least one pair of turnaround channel 5 on each side
of the steel body 20, formed by an internal guiding surface 6 and an outer
guiding surface 7, are connected endwise with and aligned to the raceway
grooves 11, 12 and the return passage 4, to form a circulation passage way
for the re-circulation of the rolling elements 3. Through the
re-circulation of the rolling elements 3, the slider 2 can slide endless
on the rail 1.
Referring to FIGS. 4A and 4B, the pair of side frames 30 are identical with
respect to each other and each includes a longitudinal arranged profiled
member 31, having the same length as the steel body 20, and two crossly
arranged endplates 32 on both end of the profiled member 31 injected in
one mold. This way, at least one longitudinally arranged all-around closed
through-hole 33 as return passage of the rolling elements 3 is provided
inside the profiled member 31. The rolling elements 3 runs inside the
profiled member 31 without any contact with the steel body 20. This design
provides a smoother running and less noise.
At least one longitudinally arranged groove 34, directly attaching to the
return passage 33, is provided for the lubricant deposit, the rolling
elements are lubricated each time when they run into the return passage 33
by re-circulation. The position of the groove 34 is designed such that the
difference of the wall thickness of the profiled member 31 is kept
uniform.
The endplates 32 are formed by a transversely arranged base plate 35,
perforated by the return passage 33 and the lubricant deposit groove 34,
on which at least one convex half-roundness 36, stretching from the inside
surface of the return passage 33, is provided as the internal guiding
surface 6 of the turnaround channel 5, a longitudinal extended side wall
37.
A longitudinally extended firm interlocking mean such as tenon 38 is
integrated and rooted on the base plate 35, such that, independent of the
profiled member 31, the tenon 38 can be designed as robust as required. A
snap means 39 is longitudinally arranged and integrated on the base plate
35, preferably direct on the tenon 38 for saving the space, for the
interlocking of the end caps 50. The endplates 32 longitudinally constrain
the steel body 20 in between.
A pair of counter parts of the interlocking means such as slots 51 formed
on the end cap 50. When the tenon 38 and the slots 51 are connected, the
end caps 50 bring the opposedly arranged side frames 30 closely toward
each other bilaterally and to a certain distance defined by the distance
between the two slots 51. The distance between the two opposing outside
surfaces 26 of the elongation of the steel body is designed to match the
distance between the two opposing side frames 30 so that side frames 30
are firmly attached to and clamped the steel body 20 bilaterally tightly.
A pair of extending walls 37, each extending from the lateral side of
profiled member 31 longitudinally, secure the joint of the turnaround
channel 5 and the return passage 4 being covered inside the side frames 30
and avoid a direct invasion of dusts into the turnaround channel 5 and the
return passage 4.
The side frames 30 are fabricated by conventional injection molding
technique using engineering plastic or metallic powder having a molding
die with additional bilateral sliding dies. The through holes 33 as a
return passage of the rolling elements and the lubricant deposit groove 34
are injection molded by a through pin having the same form as, but with a
length slightly longer than, the through hole 33 and the lubricant deposit
groove 34. The through pin is integrated on the molding die of one of the
endplates; on the molding dies of the other endplate a guiding hole for
the through pin is provided. The end of the through pin is precisely
engaged and supported by the guiding hole when the molding dies are
closed. The outer form of the profiled member 31 and the form of the
endplates 32, including the tenon 38, snap mean 39, extending wall 37,
convex half-roundness 36, etc. are injection molded on different molding
dies and thereof without any interaction to each other and able to be
designed independently.
Referring to FIG. 5, alternatively the longitudinally arranged through
holes 33 as the return passage of the rolling elements 3 are only near
half closed by the profiled member 31. The rest near half surface of the
through holes are formed by a portion of the outside surface 26 of the
elongation of the steel body 20. The surface 43 having near half close the
through hole becomes a part of the fitting surface 42 of the profiled
member 31 and is injection molded together with the fitting surface 42 of
the profiled member 31 in one molding die. Such design simplifies the
molding dies without the need of the through pin. A forcipiform of the
outside surface 26 of the elongation for the attachment between the steel
body 20 and the side frames 30 is sometimes hardly to be fulfilled by
using portion of them to form the rest near half surface of the through
holes 33. A constraining means such as a projection 41 overhead to press
the steel body 20 vertically downward is therefore required. The
projections overhead 41, longitudinally extended from the top of the
endplates 32 are engaged into the recess 27 on both ends of the top face
of the steel body 20 and press the steel body 20 from the top vertically
downward to provide a firm contact and exact positioning to the profiled
member 31. The rest portion profile of the profiled member 42 is still
provided as fitting surface for the attachment to the elongation 22 of the
steel body. The necessary accurate alignment of the perforated hole on the
endplates 32 to the concave half-roundness 52 of the end caps and the
through hole 33 respectively for the smooth running of the rolling
elements 3 is achieved by the direct positioning of the side frames 30 to
the end caps 50 and steel body 20 respectively.
Referring to FIGS. 6 and 7, the end caps 50 include at least one pair of
concave half-roundness 52, at least one pair of counterparts of the
interlocking means on the endplates such as slots 51, a right-and-left
symmetric arranged lubrication channel 53, a lubrication hole 54, and a
pair of longitudinally arranged rectangular recess 55 on the bottom of the
inside a guiding hole for the through pin is provided. The end of the
through pin is precisely engaged and supported by the guiding hole when
the molding dies are closed. The outer form of the profiled member 31 and
the form of the endplates 32, including the tenon 38, snap mean 39,
extending wall 37, convex half-roundness 36, etc. are injection molded on
different molding dies and thereof without any interaction to each other
and able to be designed independently.
Referring to FIG. 5, alternatively the longitudinally arranged through
holes 33 as the return passage of the rolling elements 3 are only near
half closed by the profiled member 31. The rest near half surface of the
through holes are formed by a portion of the outside surface 26 of the
elongation of the steel body 20. The surface 43 having near half close the
through hole becomes a part of the fitting surface 42 of the profiled
member 31 and is injection molded together with the fitting surface 42 of
the profiled member 31 in one molding die. Such design simplifies the
molding dies without the need of the through pin. A forcipiform of the
outside surface 26 of the elongation for the attachment between the steel
body 20 and the side frames 30 is sometimes hardly to be fulfilled by
using portion of them to form the rest near half surface of the through
holes 33. A constraining means such as a projection 41 overhead to press
the steel body 20 vertically downward is therefore required. The
projections overhead 41, longitudinally extended from the top of the
endplates 32 are engaged into the recess 27 on both ends of the top face
of the steel body 20 and press the steel body 20 from the top vertically
downward to provide a firm contact and exact positioning to the profiled
member 31. The rest portion profile of the profiled member 42 is still
provided as fitting surface for the attachment to the elongation 22 of the
steel body. The necessary accurate alignment of the perforated hole on the
endplates 32 to the concave half-roundness 52 of the end caps and the
through hole 33 respectively for the smooth running of the rolling
elements 3 is achieved by the direct positioning of the side frames 30 to
the end caps 50 and steel body 20 respectively.
Referring to FIGS. 6 and 7, the end caps 50 include at least one pair of
concave half-roundness 52, at least one pair of counterparts of the
interlocking means on the endplates such as slots 51, a right-and-left
symmetric arranged lubrication channel 53, a lubrication hole 54, and a
pair of longitudinally arranged rectangular recess 55 on the bottom of the
inside surface. The end caps 50 interlock the two side frames 30 crossly
together by connecting the tenon 38 on the endplates 32 with the slots 51
on the end caps 50. The side frames 30 are approached against each other
to a certain distance defined by the distance between the two slots 51.
The distance of the two opposing outside surfaces 26 of the elongation of
the steel body is designed to match the distance between the two opposed
side frames 30 so that the side frames 30 are therefore firmly attached to
and clamped to the steel body 20 bilaterally tightly with a certain
pressure predefined. The end caps 50 are also transversely and fixedly
attached to the side frames 30 through the connection of the tenon 38 and
the slots 51. The end caps are positioned directly to the side frames
through the engagement of the positioning means on the endplates,
preferably the same parts as the tenon 38, and its inter-fitting mean,
preferably the same parts as the slots 51. A pair of recesses 56 on both
lateral side surfaces of the end caps 50 are provided for the engagement
of the side wall 37 on the endplates. A pair of the rectangular recesses
55 with an opening from the bottom of the inside surface and extending
vertically upwards then longitudinally outwards are provided for the
engagement with the projections on both end of the underseals.
The concave half-roundness 52 on the end caps 50, as the outer guiding
surface of the turnaround channel 7, together with the convex
half-roundness 36 on the endplates 32, directly stretching from the inside
surface of the return passage without any misalignment in between, forms a
closed turnaround channel 5. The end of the concave half-roundness 52 is
therefore more precisely aligned to the end of the through hole 33 as
return passage through the direct positioning between the end caps 50 and
the side frames 30. This design brings a more smooth-running of the
rolling elements re-circulation.
A lubrication hole 54 is provided in the middle of the end cap 50 and a
right-and-left symmetric arranged lubrication channel 53 connects the
lubrication hole 54 and the turnaround channel 5 on bilateral side, so
that lubricant can be refilled from the lubrication hole 54 into the
re-circulation passage ways of the rolling elements 3. The base plate 35
of the end plate closes the lubrication channel 53 when the end cap 50 is
interlocked together with the side frames 30. To avoid the leakage of
lubricant from the joint gap of the base plates of the two opposed
endplates 32, a design of the laterally extended projections 40 having
longitudinal overlap to each other and a design with overhangs 57 from the
end cap 50 to close the joint gap on top an bottom are provided.
Referring to FIGS. 8 and 9, two end seals 70 are formed by a rigid layer
71, such as steel sheet, and an elastic layer 72, such as molded by
rubber. The rigid layer 71 has two slots 73 on bilateral side, which will
be longitudinally engaged by the snap means 39 on the endplate of the side
frames. The end seals 70 with the end caps 50 will together be
longitudinally interlocked on the slider 2 by means of the snap means 39
without using any screw. Two positioning holes 75 on the steel back engage
the positioning pins 58 formed on the end caps 50 and the end seals 70 are
thereof vertically and transversely fixed attached and positioned to the
end caps 50 tightly. The elastic layer 72 comprises a sealing lip 77,
having the same shape as the profile of the rail 1, which provides a
contact sealing effect to prevent any invasion of dirty particles or dusts
from the front and back sides into the inside of the slider 2. The elastic
layer 72 has recesses 78, which are open only in half of the slots 73 on
the rigid layer 71. When the end seals 70 are longitudinally moved to the
slider 2, the snap means 39 are engaged into the slots 73; the rubber
layer 72 will be squeezed outward and sideward by the snap means 39. When
the snap means 39 are free to rebound back to the interlocking position,
the snap means 39 and the rubber layer 72, because of it elasticity, will
rebound back and return to its original position. The elastic layer 72
covers the rest opening of the slots 73 and prevents the snap means 39
escaping from its interlocking position unexpectedly (shown in FIG. 10).
A through hole 74 on the end seals 70 aligned to the lubrication hole 54 on
the end caps 50 is provided so that lubricant can be charged into the
lubrication channel 53 of the end caps 50 from outside. Because of the
dimension of the small sized linear rolling guide device, the lubrication
hole 54 cannot be attached with a grease nipple any more. Lubricant will
leak from and dusts invade into the lubrication holes 54. The elastic
layer 72 is molded with a plug 76, having the same form as and aligning to
the lubrication hole on the end caps of the slider. The plug 76 is
partially connected with the elastic layer and because of its elasticity
thereof can be unfolded. The plug 76 is unfolded while lubrication
injection and plugged into the lubrication hole 54 after the lubrication
injection is fulfilled, so that the leakage of the lubricant from the
lubrication hole 54 is prevented (shown in FIG. 11).
For the positioning of the end seals 70 to the end caps 50, a positioning
pin 58 on the end caps 50 and a position hole 75 on the end seals 70 are
provided.
Referring to FIG. 12, a pair of under seals 80 with a laminated structure
are provided, each has a thin rigid back 81, such as from steel sheet,
instead of the usual thick rigid back and an elastic layer 82, such as
molded from rubber. To have the same rigidity as the thick rigid back, a
rib 83 is bent upward on the longitudinally outer edge of the thin rigid
back 81. The rib is engaged with the longitudinally arranged gap 44 on the
bottom between the profile member 31 and the elongation 22 of the steel
body (shown in FIG. 2). The under seals 80 are laterally positioned to the
slider 2. On both near ends of the rigid back 81, a projection 84 is
formed and bent vertically upward and then longitudinally outward. The
under seals 80 are fastened and attached to the slider by inserting the
projections 84 into the rectangular recess 55 on the bottom of the end
caps 50. Alternatively the projections 84 on the end of the rigid body are
inserted into the recesses 79 on the bottom of the end seals 70, and an
escaping recesses 60 for the upward portion of the projection 84 is formed
on the adjacent end caps 50. Such an interlocking design allows the bottom
of the end caps 50 and the end seals 70 to have the same height as the
bottom of the steel body 20 and prevents it to occupy any space of the
clearance from the bottom of the rail 1 to the bottom of the slider 2. If
such clearance is not sufficient enough especially in the small size
linear motion rolling guide device (1.about.2 mm), an interference between
the slider and the mounting shoulder for the rail is subject to happen.
The clearance will also only reduce the thickness of the under seals 80
when the under seals 80 are mounted. A compact design without waste the
space of the clearance is thus achieved. The elastic layer 82 provides a
longitudinally extended sealing lip 85, which contacts with the side
surface of the guide rail 1 and prevents the dusts or particles entering
into the race way 11, 12 of the rolling elements 3.
Referring to FIG. 14, to prevent the dropout of the rolling elements when
separating the slider from the rail, a retainer 90, having a straight
portion 91 and two holding portions 92 on both end of the straight
portion, made from a steel string or wire, is provided. Through an
accurate positioning of the holding porting 92 to the end caps 50 the
longitudinally arranged straight portion 91 is situated in the same height
as the rolling elements 3 vertically and in the adjacent outside of the
rolling elements 3 laterally. The width between the retainer 90 and the
edge of the raceway 21 of the steel body is smaller than the diameter of
the rolling elements 3. The rolling elements 3 are therefore held in
between. An escaping recess 12 on the raceway 11 of the rail is provided,
so that there is no contact between the rail 1 and the retainer 90 when
the slider 2 slides on the rail 1. The holding portion 92 has a first
portion 93 transversely and laterally bent outward and a second portion 94
transversely and vertically bent upward. The vertical and the lateral
positions of the retainer 90 are defined by the engagement of the recesses
59 on the outer end of the end caps with the first and the second portion
93, 94 respectively.
Other embodiments of the invention will appear to those skilled in the art
from consideration of the specification and practice of the invention
disclosed herein. It is intended that the specification and examples to be
considered as exemplary only, with a true scope and spirit of the
invention being indicated by the following claims.
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